Doing theory with the lights out
What kind of theory can be built around something that cannot be measured? Do we need more to explain more?
In "Out There," Richard Panek describes a universe complicated by the inferred presence of dark matter and dark energy, substances that cannot be seen, touched, measured, sliced, diced or otherwise put under the figurative microscope. The universe might be radically different than first presumed.
And Panek's prose isn't bad either:
Since the invention of the telescope four centuries ago, astronomers have been able to figure out the workings of the universe simply by observing the heavens and applying some math, and vice versa. Take the discovery of moons, planets, stars and galaxies, apply Newton’s laws and you have a universe that runs like clockwork. Take Einstein’s modifications of Newton, apply the discovery of an expanding universe and you get the big bang. 'It’s a ridiculously simple, intentionally cartoonish picture,' [cosmologist Saul] Perlmutter said. 'We’re just incredibly lucky that that first try has matched so well.'
But is our luck about to run out? [2006 Nobel Prize winner George] Smoot’s and Perlmutter’s work is part of a revolution that has forced their colleagues to confront a universe wholly unlike any they have ever known, one that is made of only 4 percent of the kind of matter we have always assumed it to be — the material that makes up you and me and this magazine and all the planets and stars in our galaxy and in all 125 billion galaxies beyond. The rest — 96 percent of the universe — is ... who knows?
“Dark,” cosmologists call it, in what could go down in history as the ultimate semantic surrender. This is not “dark” as in distant or invisible. This is “dark” as in unknown for now, and possibly forever.
If so, such a development would presumably not be without philosophical consequences of the civilization-altering variety. Cosmologists often refer to this possibility as “the ultimate Copernican revolution”: not only are we not at the center of anything; we’re not even made of the same stuff as most of the rest of everything. “We’re just a bit of pollution,” Lawrence M. Krauss, a theorist at Case Western Reserve, said not long ago at a public panel on cosmology in Chicago. “If you got rid of us, and all the stars and all the galaxies and all the planets and all the aliens and everybody, then the universe would be largely the same. We’re completely irrelevant.”
All well and good. Science is full of homo sapiens-humbling insights. But the trade-off for these lessons in insignificance has always been that at least now we would have a deeper — simpler — understanding of the universe. That the more we could observe, the more we would know. But what about the less we could observe? What happens to new knowledge then? It’s a question cosmologists have been asking themselves lately, and it might well be a question we’ll all be asking ourselves soon, because if they’re right, then the time has come to rethink a fundamental assumption: When we look up at the night sky, we’re seeing the universe.
Not so. Not even close.